6 Chapter Databases and Information Management

File Organization Terms and Concepts Bit: Smallest unit of data; binary digit (0,1) Byte: Group of bits that represents a single character Field: Group of words or a complete number Record: Group of related fields File: Group of records of same type ORGANIZING DATA IN A TRADITIONAL FILE ENVIRONMENT Management Information Systems Chapter 7 Managing Data Resources

Database: Group of related files Entity: Person, place, thing, event about which information is maintained Attribute: Description of a particular entity Key field: Identifier field used to retrieve, update, sort a record ORGANIZING DATA IN A TRADITIONAL FILE ENVIRONMENT Management Information Systems Chapter 7 Managing Data Resources File Organization Terms and Concepts (Continued)

ORGANIZING DATA IN A TRADITIONAL FILE ENVIRONMENT The Data Hierarchy Figure 7-1 Management Information Systems Chapter 7 Managing Data Resources

ORGANIZING DATA IN A TRADITIONAL FILE ENVIRONMENT Entities and Attributes Figure 7-2 Management Information Systems Chapter 7 Managing Data Resources

Problems with the Traditional File Environment Data Redundancy and Inconsistency: Data redundancy: The presence of duplicate data in multiple data files so that the same data are stored in more than one place or location Data inconsistency: The same attribute may have different values. ORGANIZING DATA IN A TRADITIONAL FILE ENVIRONMENT Management Information Systems Chapter 7 Managing Data Resources

The coupling of data stored in files and the specific programs required to update and maintain those files such that changes in programs require changes to the data Lack of flexibility: A traditional file system can deliver routine scheduled reports after extensive programming efforts, but it cannot deliver ad-hoc reports or respond to unanticipated information requirements in a timely fashion. ORGANIZING DATA IN A TRADITIONAL FILE ENVIRONMENT Management Information Systems Chapter 7 Managing Data Resources Program-data dependence: Problems with the Traditional File Environment (Continued)

Because there is little control or management of data, management will have no knowledge of who is accessing or even making changes to the organization’s data. Lack of data sharing and availability: Information cannot flow freely across different functional areas or different parts of the organization. Users find different values of the same piece of information in two different systems, and hence they may not use these systems because they cannot trust the accuracy of the data. ORGANIZING DATA IN A TRADITIONAL FILE ENVIRONMENT Management Information Systems Chapter 7 Managing Data Resources Poor security: Problems with the Traditional File Environment (Continued)

ORGANIZING DATA IN A TRADITIONAL FILE ENVIRONMENT Traditional File Processing Figure 7-3 Management Information Systems Chapter 7 Managing Data Resources

Database Management System (DBMS) Software for creating and maintaining databases Permits firms to rationally manage data for the entire firm Acts as interface between application programs and physical data files Separates logical and design views of data Solves many problems of the traditional data file approach THE DATABASE APPROACH TO DATA MANAGEMENT Management Information Systems Chapter 7 Managing Data Resources

The Contemporary Database Environment THE DATABASE APPROACH TO DATA MANAGEMENT Figure 7-4 Management Information Systems Chapter 7 Managing Data Resources

Components of DBMS: Data definition language: Specifies content and structure of database and defines each data element Data manipulation language: Used to process data in a database. Example: SQL (structured query language) Data dictionary: Stores definitions of data elements and data characteristics THE DATABASE APPROACH TO DATA MANAGEMENT Management Information Systems Chapter 7 Managing Data Resources

Types of Databases: Relational DBMS Hierarchical and network DBMS Object-oriented databases THE DATABASE APPROACH TO DATA MANAGEMENT Management Information Systems Chapter 7 Managing Data Resources

Relational DBMS: Represents data as two-dimensional tables called relations Relates data across tables based on common data element Examples: DB2, Oracle, MS SQL Server THE DATABASE APPROACH TO DATA MANAGEMENT Management Information Systems Chapter 7 Managing Data Resources

The Relational Data Model THE DATABASE APPROACH TO DATA MANAGEMENT Figure 7-6 Management Information Systems Chapter 7 Managing Data Resources

Three Basic Operations in a Relational Database: Select: Creates subset of rows that meet specific criteria Join: Combines relational tables to provide users with information Project: Enables users to create new tables containing only relevant information THE DATABASE APPROACH TO DATA MANAGEMENT Management Information Systems Chapter 7 Managing Data Resources

The Three Basic Operations of a Relational DBMS THE DATABASE APPROACH TO DATA MANAGEMENT Figure 7-7 Management Information Systems Chapter 7 Managing Data Resources

Hierarchical and Network DBMS Organizes data in a tree-like structure Supports one-to-many parent-child relationships Prevalent in large legacy systems THE DATABASE APPROACH TO DATA MANAGEMENT Hierarchical DBMS: Management Information Systems Chapter 7 Managing Data Resources

A Hierarchical Database for a Human Resources System THE DATABASE APPROACH TO DATA MANAGEMENT Figure 7-8 Management Information Systems Chapter 7 Managing Data Resources

Hierarchical and Network DBMS Depicts data logically as many-to-many relationships THE DATABASE APPROACH TO DATA MANAGEMENT Network DBMS: Management Information Systems Chapter 7 Managing Data Resources

The Network Data Model Figure 7-9 Management Information Systems Chapter 7 Managing Data Resources THE DATABASE APPROACH TO DATA MANAGEMENT

Hierarchical and Network DBMS Outdated Less flexible compared to RDBMS Lack support for ad-hoc and English language-like queries Disadvantages: Management Information Systems Chapter 7 Managing Data Resources THE DATABASE APPROACH TO DATA MANAGEMENT

Object-oriented DBMS: Stores data and procedures as objects that can be retrieved and shared automatically Object-relational DBMS: Provides capabilities of both object-oriented and relational DBMS Object-Oriented Databases: Management Information Systems Chapter 7 Managing Data Resources THE DATABASE APPROACH TO DATA MANAGEMENT